Jury hears DNA witnesses during 1st-degree murder trial of man accused in death of B.C. teen

WARNING: This story contains graphic content and may affect those who have experienced sexual violence or know someone affected by it.

After weeks of delays, the trial of a man accused of murderinga Burnaby teen resumed with a pair of expert DNA witnesses testifying before the jury.

Christine Crossman, a forensic biologist with the RCMP, continued her testimony which had been on hold since she last stood before the jury on May 25 when sheexplained what DNA is and how the RCMP's forensic lab works.

On Monday, Crossmansaid the Integrated Homicide Investigation Team transferred 14 exhibits to the RCMPsNational Forensic Laboratoryduring the investigation into the teen's death, including 13 that were extracted from the 13-year-old victim.

The other was a DNA sample police recovered from Ibrahim Ali, the man accused of first-degree murder.

The jury did not hear how police came into possession of Ali's DNA.

Crown prosecutors contendthevictim was passing through Burnaby's Central Park on July 18, 2017. She was on a trail, likely wearing earbuds,when she was attacked and dragged into the woods before she was sexually assaulted and strangled.

Prosecutors say Ali's DNA was recovered from her body.

The victim's name is protected by a publication ban.

Chain of custody

Crossman outlinedhow samples are managed within the lab, including a "chain of custody" or a record of each person who handles a sample, where samplesarestoredand if any alterations are made.

Each person who handles a sample is responsible for scanning a unique barcode and entering a PIN into the lab's management system.

Crossman called the system secure, with "checks and balances" in place to detect and review any potential record-keeping errors.

Defence counsel did not have the opportunity to cross-examine Crossman on the reliability of the RCMP's forensic lab records. Instead, Crossman is expected to return to the witness stand at the end of the DNA evidence portion of the trial.

Jeremy Fenn, a search technologist at the lab who is considered an expert in identifying biological trace evidence, including blood, semen, and saliva, also took the stand on Monday, where he was questioned about his training and qualifications. He is among the lab workers who reviewed samples.

Fenn is expected to continue his testimony on Tuesday.

Support is available for anyone who has been sexually assaulted. You can access crisis lines and local support services through thisGovernment of Canada websiteor theEnding Violence Association of Canada database. If you're in immediate danger or fear for your safety or that of others around you, please call 911.